Automatic mine-door.



PATENTED JUNE 27, 1905.

O. W. LUNDHOLM. AUTOMATIC MINE DOOR.

APPLICATION FILED JUNE I 1904.

3 SHEETSSHEET- 1.

lam- 4 #W PATENIED JUNE 27, 1905.

0 W. LUNDHOLM. AUTOMATIC MINE DOOR.

APPLICATION FILED JUNE 1, 1904.

3 SHEETS-SHEET B.

No. 793,452. PATENTED JUNE 27, 1905. 0. W. LUNDHOLM.

AUTOMATIC MINE DOOR.

APPLICATION FILED JUNE 1, 1904.

3SHEETS-SHEET 3.

NITED STATES Patented June 27, 1905.

PATENT FFICE.

AUTOMATIC MINE-DOOR.

SPECIFICATION forming part of Letters Patent NO. 793,452, dated June2'7, 1905.

Application filed June 1,1904. Serial No. 210,683.

To all whom it may concern.-

Be it known that I, O'r'ro W. LUNDHOLM, a citizen of the United States,residing at Des Moines, in the county of Polk and State of Iowa, haveinvented a certain new and useful Improvement in Automatic Mine-Doors,of which the following is a specification.

The objects of my invention are to provide an automatic trap-doorespecially designed for use in mines to prevent the escape of air fromthe mines and to automatically open and close when a mine-car approachesand passes beyond the same, and, further, to provide means forautomatically locking the doors in their open position, so thatair-currents will not swing them when a car is passing through adoor-opening.

My invention consists in certain details in the construction,arrangement, and combination of the various parts of the door anddooroporating mechanism, as hereinafter more fully set forth, pointedout in my claims, and illustrated in the accompanying drawings, in whiclFigure 1 shows a perspective view of the complete door anddoor-operating mechanism, showing the door in its closed position. Fig.2 shows a top or plan view of same with the door in its open position.The dotted lines indicate the closed position of the door. Fig. 3 showsa side elevation of the complete minedoor and connected parts. Thedotted lines in this figure indicate the open position of the door andthe arrangement of the operating mechanism and look when the door isopen. Fig. 4 shows an end view of a mine-car upon a track and the-leverby which the door is operated inits position adjacent to the car-wheel.Fig. 5 shows a perspective view of the lever for operating the mine-doorand connected parts, and Fig. 6 shows a detail sectional view of part ofone of the mine-doors and the lever connected therewith by which thedoor is opened and closed.

Referring to the accompanying drawings, I have used thereference-numeral 10 to indicate a framework to be placed in amine-entry at the point where the door is to be located. The numeral 11indicates a railway-track running through the said frame.

direction of the interior of the mine.

The door proper is composed of two doorsections, in their closedposition arranged at about right angles to each other. The meeting edgesof the door-sections project in the These door-sections are indicated bythe numeral 12 and each is provided with a handle 13 near its inneredge. The door-sections are pivotally supported at their upper ends bythe pins 14, which are mounted in suitable bearings in the frame 10, andat their lower ends by the pins 15, which are supported in brackets 16at the bottom of the mine-entry.

The upper and lower pins of each door-section are in line with eachother and are arranged nearer to the outer end of the section than tothe inner end. This is done for the reason that the air-pressure uponthe inner end portions of the door-sections will be greater than uponthe outer end portions, so that this air-pressure itself serves to holdthe door-sections firmly together, and yet a part of the air-pressure isthrown upon the outer portion of the door-sections, so thatcomparatively little power is required to overcome the air-pressure whenit is desired to open the door. In this connection I have provided meanswhereby the quantity of air escaping through the doorway when the dooris open is reduced to a minimum, as follows: The nu meral 17 indicates astationary partition arranged adjacent to the outer end of eachdoorsection and extending from the top to the bottom of the mine-entryand from the sidewalls inwardly to a point adjacent to the track 11, andthe inner edge of said partition is arranged to be engaged by the outeredges of the adjacent door-sections when the door-section is open, asclearly shown in Fig. 2, thus preventing the passage of air through thedoorway outside of the doors and permitting the air to pass through thedoorway only through the space between the doors when they are open.

I have provided for opening and closing the door as follows: The numeral18 indicates a rock-shaft, mounted in suitable supportings beneath thedoor and provided with arms 19 at its ends. At the top of each of thearms 19 is a pivoted bracket 20, which bracket is connected to a bracket21 on the adjacent door-section by means of link 22. Hence when theshaft 18 is rocked in a direction to throw the arm 19 rearwardly towardthe doorseetion the said door-section will be opened, because thebrackets 21 are fixed to the doorsections outside of their pivotalcenters, and when their arms 19 are moved in the opposite direction thedoors will be closed. On one end of the shaft 18 I have fixed an arm 23,having a pin 24 fixed to its upper end, and the numeral 25 indicates alink provided with slots 26 at its sides, through which the said pin 24is passed, thus permitting the link to move longitudinally a limiteddistance before moving the arm 23. Connected to the upper end of the arm23 is a bracket 27, in which I have pivoted a bell-crank lever 28, theupper end of which passes through thelink 25. The numeral 29 indicates arod pivoted at its upper end to the lower end of the bell-crank lever28. Near the lower end of the rod 29 is an extension 29, which isslidingly held to the arm 23 by thebracket 29. The lower end of the rod29 is beveled. By this construction it is obvious that when the link 25is moved in one direction the lever 28 will be tilted to move the rod 29downwardly and when the link 25 is moved in another direction said rodwill be elevated relative to the arm 23. In Fig. 3 the solid lines showthe rod 29 elevated and the dotted lines show it lowered. The numeral 30indicates a bracket fixed to a stationary support adjacent to the lowerend of the arm 23, and said bracket is provided with a lug 31. This lugis so positioned that when the arm 23- is moved to its limit toward thedoor the lower end of the rod 29 will engage the lug 31 and lock the arm23 against movement in the opposite direction, and said arm 23 canbemoved in a direction away from the door only if the link 25 has beenmoved as required,to elevate the rod 29. When the arm 23 is moved to itslimit toward the door by means other than that imparted by the link 25,then the rod 29 does not engage the lug 31. This is desirable for thefollowing reasons: When the door is opened or closed automatieally by acar, then the link 25 is always operated before the arm 23 is moved.Hence when the door is opened it will be locked in this position, sothat it cannot swing when a car is passing through the door-opening; butwhen a door is opened by hand-as, for instance, when a person desires towalk through a door-opening-then the link 25 is not operated first, andthe door may be opened either partly or wholly by hand and closed byhand without being locked in its open position, for if it were locked itcould be opened only by the operator passing to the nearestleverdesigned to engage a ear-wheel,and this operation would takeconsiderable time and leave the door open longer than necessary. I haveprovided for operating the link 25 in the proper direction for openingand closing the door when a car approaches or passes beyond the door ineither direction, as required, to firstopen and then close the door, asfollows: At a suitable distance from the door on either side are theuprights 32, in each of which I have mounted a rock-shaft 33. On one endof each rock-shaft 33 is a lever 34. Attached to the top of one of thelevers 34 is a wire or cable 35, the other end of which is attached tothe lower end of the opposite lever 34, and attached to the lower end ofthe first lever 34 is a wire or cable 36, attached to the adjacent endof the link 25, and a similar wire or cable 37 is attached to the otherend of the link 25 and to the top of the other lever 34, as clearlyshown in Fig. 3.

Fixed to the inner end of each of the rockshafts 33 is a slottedsegmental guide 38, and pivotally mounted on the same end of the shaftisatrip-arm 39, the upper end of which projects through the slot in theguide 38 and the lower end of which projects downward in position to beengaged by a ear-wheel passing over the track 11. The lower end of thearm 39 is materially heavier than the upper end, and hence always hangsstraight downward except when moved by the passing car-wheel.

In practical use and assuming that a car is approaching the closed doorfrom the side toward which the door-sections project-as, for instance,from the left in Fig. 1the'first carwheel will strike upon the arm 39and push it toward the door, thus moving the guide 38 away from thedoor, because the upper end of arm 39 will be in engagement with the endof the slotted guide farthest away from the door. This will rock theshaft 33 as required to move the upper end of the adjacent lever 34 awayfrom the door. This movement will cause the wire or cable 35 to pull thelower end of the opposite lever 34 toward the door, thus throwing theupper end of the said opposite lever away from the door and moving thelink 25 toward the door. The first effect of this movement of the link25 toward the door will be to release the bell-crank lever 28 and permitthe rod 29 to engage thelug 31. The further movement of the link 25 willthen move the arm 23 toward the door, thus rocking the shaft 18 andcausing the arms 19 to push the outer ends of the door-sections in thedirection required for opening the door sections, and when thedoor-sections are open the bolt 29 drops by gravity behind the lug31,thus locking the door-sections in their open position. Then the car haspassed through the door, it will engage the arm 39 at the opposite sideof the door and move the link 25, as required, first to release the bolt29 and then to swing the door-sections to their closed positions. Inthis way the door-sections are automatically opened by a car approachingfrom either direction, then automatically locked in their open position,and finally released and closed' as the car passes beyond the door.

\Yh n a person approaches the door from the sil toward which thedoor-sections are projeeti ng, he may open them easily by grasping oneof the handles 13 and may then pass through the door and close it byhand without having the door locked. Furthermore, when the doors areclosed the air-pressure from the inside of the mine-entry will tend tohold them closed to prevent leakage of air through the door-opening,because the preponderance of surface of the door-sections is exposed tothe air-pressure, and yet the doorseetions may be easily opened, becausethere is considerable air-pressure on the outer ends of thedoor-sections. Furthermore, by providing the partitions 17 the air isprevented from passing through the entry outside of the door-sectionswhen they are open, and this air-pressure is prevented from moving orclosing the door-sections when they are in their open positions onaccount of the automatic lock.

Having thus described my invention, what I claim, and desire to secureby Letters Patent of the United States therefor, is

1. The combination of two door-sections, in their closed positionsstanding approximately at right angles to each other and means forpivotally supporting each of said door-sections at its upper and lowerends at points between its center and outer end, and stationarypartitions arranged to engage the outer ends of the door-sections whensaid sections are in their open positions.

2. The combination of a door-frame, two door-sections pivotally mountedin the frame to swing in horizontal planes, and stationary partitionsarranged to stand adjacent to the outer ends of the said door-sections,when in their open positions.

3. The combination of a door, a rock-shaft, a slotted segmental guidefixed to one end of the shaft, an arm pivotally mounted on the shaftwith one end in the slotted guide, a lever fixed to the shaft and meansconnected with the lever for operating the door.

4. The combination of a door, two rock shafts pivotall y supported atopposite sides of the door, each having a segmental slotted guide fixedto one end, an arm pivoted to the same end with one end in the slottedguide, and a lever fixed to the other end, means for connecting thelower end of one of said levers with the upper end of the other, meansfor connecting the upperend of the first-mentioned lever with the lowerend of the other, and means operating'by one of said connecting meansfor opening and closing the door.

5. The combination of two d cor-sections each pivotally supported at itsupper and lower ends, a rock-shaft mounted beneath the doorsections, anarm fixed to each end of said rockshaft, a bracket pivoted to each arm,a link pivoted to each bracket, and to the adjacent door-section, andmeans for rocking said shaft to open and close the door-sections.

6. The combination of two door-sections each pivotally supported at itsupper and lower ends, a rock-shaft mounted beneath the door sections, anarm fixed to each end of said rockshaft, a bracket pivoted to each arm,a link pivoted to each bracket, and to the adjacent door-section, meansfor rocking said shaft to open and close the door-sections, and meansfor automatically locking the rock-shaft when the door-sections are intheir open positions.

7. The combination of two door-sections each pivotally supported at itsupper and lower ends, a rock-shaft mounted between the doorsections, andan arm fixed to each end of said rock-shaft, a bracket pivoted to eacharm, a link pivoted to each bracket, and to the adjacent door-section,means for rocking said shaft to open and close the door-sections, meansfor automatically locking the rock-shaft when the door-sections are intheir open positions, said means comprising an arm fixed to therockshaft a slide rod mounted on said arm, a bracket secured to astationary support and provided with a lug to be engaged by theslide-rod when the door-sections are open, and means for jointlyoperating the said arm and slide-rod.

8. The combination of two door-sections pivotally supported at theirupper and lower ends, a rock-shaft beneath the door-sections, arms atthe ends of the rock-shaft, means for connecting said arms with thedoor-sections, an arm fixed to one end of the shaft, a bell-crank leverpivoted to said arm, a slide-rod pivoted to the bell-crank lever, astationary lug to be engaged by the slide rod, a link slidingly mountedat the upper end of said arm and having slotted sides, a pin mounted inthe arm and passing through the slotted sides, said links when moved inone direction first operating the bell-crank lever to elevate thesliderod and then moving the arm, and said link when moved in theopposite direction first releasing the bell-crank lever to permit theslide- I rod to descend and then operating the arms,

and means actuated by a vehicle for moving said link substantially asand for the purposes stated.

OTTO WV. LUNDHOLM.

Witnesses:

O. O. GREENLEE, JOHN EDWARDS.

IIO

